This invention relates to a method for manufacturing a three-dimensional circuit substrate.
Conventionally, flat pieces of circuit substrate have been used and are generally referred to as printed circuit boards or PCBs; however, a circuit substrate having various three-dimensional configurations and a method for manufacturing the circuit substrate could enhance the precision and reliability of various electric components connected to the circuit substrate.
The manufacturing of a three-dimensional circuit substrate through two-composition molding is known in the art. In this method, a solid, on which electroless plating can be applied, is first molded through injection molding by using resin with a plating catalyst mixed therein. Second, a layer, on which electroless plating is not applied, is formed on a given surface of the molded solid through another injection molding process using another resin without the plating catalyst. Last, the electroless plating is applied onto the solid except the layer. A conducting portion is thus formed on the desired surface of the molded solid.
In another known method, a solid is first molded by using resin which can be plated electrolessly. Subsequently, photo-resist is applied on the surface of the molded solid and a circuit pattern is exposed. After the photo-resist is partially removed through etching, electroless plating is applied on the etched surface of the molded solid, thereby forming a three-dimensional circuit substrate.
In another known method, a three-dimensional substrate is formed and a circuit pattern is transferred onto the surface of the three-dimensional substrate using a transfer film.
The forming of a conductive portion comprising a circuit pattern on the given surface of a three-dimensional substrate through vacuum evaporation has also been proposed.
The above mentioned methods, however, involve intricate process steps such as injection molding with the resin including the plating catalyst, the forming of the circuit pattern with transfer film, or vacuum evaporation. A three-dimensional substrate according to these prior art techniques is thus difficult to manufacture.
Wherefore, an object of this invention is to provide a method that can easily manufacture a three-dimensional circuit substrate comprising a complicated circuit pattern.
Other objects and benefits of the invention will become apparent from the detailed description which follows hereinafter when taken in conjunction with the drawing figures which accompany it.